If you've a head for heights and a love for a bit of London heritage, the Tower Bridge exhibition today lifts the covers off its new glass walkway, spanning the Thames 42 metres above the river.

Costing £1 million to install, it's part of Tower Bridge's anniversary celebrations, marking 120 years of the bascule suspension bridge being in service.

The glass walkway stretches for 11m long and 1.8m wide, and is made from six reinforced glass panels, each 68mm thick. Some of the bridge's steelwork has been removed to improve the view of the working lifting arms below, making for the most significant change to the 120-year old bridge since the opening of its visitor centre in the early 1980s.

The West Walkway of the bridge opens today, with the East Walkway due to open on December 1st. Adult tickets start at £8 if you buy them online, children at £3.50 and concessions and students £5.50. [Tower Bridge]